Antiphospholipid antibodies, such as anti-beta2-glycoprotein I (beta2GPI), are present in
multibacillary leprosy (MB) patients; however, MB patients do not usually present with
antiphospholipid antibody syndrome (APS), which is characterized by thromboembolic phenomena (
TEP). Rare cases of
TEP occur in
leprosy patients, but the physiopathology of this condition remains unclear. In this case-control study, we examined whether single-nucleotide polymorphisms (SNPs) of the beta2GPI gene contributed to the risk of
leprosy and APS co-morbidity. SNPs Ser88Asn, Leu247Val, Cys306Gly and Trp316Ser were identified in 113 Brazilian
leprosy patients. Additionally, anti-beta2GPI
antibodies and plasma concentrations of beta2GPI were quantified. The Ser88Asn, Cys306Gly and Trp316Ser SNPs were not risk factors for APS in
leprosy. A higher frequency of
Val/Val homozygosity was observed in
leprosy patients compared to controls (36 vs. 5%; P < 0.001). Forty-two percent of MB and 17% of
paucibacillary leprosy patients were positive for anti-beta2GPI
IgM (P = 0.014). There was no correlation between SNP Ser88Asn or Cys306Gly and anti-beta2GPI antibody levels. In MB patients with positive anti-beta2GPI
IgM, the frequency of
Val/Val homozygosity was higher than in controls (32 vs. 15%; P = 0.042). The frequency of the mutant allele Ser316 was higher in MB patients with positive rather than negative anti-beta2GPI
IgM levels (6 vs. 0%; P = 0.040) and was greater than in the control group (6 vs. 1%; P = 0.034). The studied polymorphisms did not influence the plasma concentrations of beta2GPI. These results suggest that Leu247Val and Trp316Ser SNPs may represent genetic risk factors for anti-beta2GPI antibody production in MB patients.